German Patent Application DE 20 2010 017 605 U1 describes a brake booster, as well as a method and a device for its operation. For the controlling/regulation of the brake booster, a control device is described that controls the brake booster on the basis of signals of a sensor device for ascertaining a displacement path of an input rod, and on the basis of signals of a motor of the brake booster. Optionally, signals of a difference path sensor for determining a relative deflection between the input rod and a booster body, or of a force sensor for determining a driver's applied force, can also be evaluated by the control device.
In driving situations with braking, it can happen that excessively high pressures occur in the brake system due to the simultaneous buildup of brake pressure from the driver, the brake booster, and the recirculation of the ABS/ESP recirculation pump. These high pressures impair the brake pedal haptic feedback, and unnecessarily load the brake system. This is irritating to the driver, because the driver is not accustomed to this deviation. An object of a method according to the present invention is to control the pressure in the brake system in a manner appropriate to the situation in the case of an ABS regulation, i.e., if the ABS/ESP recirculation pump can recirculate large volumes, in such a way that the brake pedal haptic feedback is perceived as pleasant, the brake performance (minimum possible brake path) can be ensured, and the load on the brake system is as small as possible so as not to overload the brake system components.
The core of the present invention is the ascertaining of the necessary pressure target values in the brake system on the basis of the current driver behavior, the state of the brake apparatus, and the roadway surface, as well as further characteristic values of the driving situation, e.g., the vehicle speed. The target pressure value ascertained in this way is set using an electronic brake booster. In this way, the load on the brake system is limited in a manner appropriate to the situation.